Shock energy absorber

ABSTRACT

A shock absorber includes damping material in a solid state and which transitions from a solid to a viscous fluid state when stressed and a plunger device including a depending blade positioned in or adjacent the damping material to be driven into the damping material when impacted transitioning the damping material to a viscous fluid state absorbing the impact.

RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 12/925,354 filed Oct. 19, 2010 which claims thebenefit of and priority to U.S. Provisional Application Ser. No.61/281,314 filed on Nov. 16, 2009, each of which is incorporated hereinby reference, under 35 U.S.C. §§119, 120, 363, 365, and 37 C.F.R. §1.55and §1.78.

FIELD OF THE INVENTION

The subject invention relates to energy absorption.

BACKGROUND OF THE INVENTION

Generally, shock absorbers are oleo type or oleo-pneumatic type in whichthe oil is forced to pass through a plurality of orifices within acylinder-piston arrangement under increasing pressure caused by theimpacting force and thereby damping out the relative motion between thecylinder and piston as well as attenuating the transmitted forcemagnitude. Alternative shock absorbers may use a thin-walled hollowcylinder which crumples and absorbs energy under impact condition. Thephysical dimensions of such shock absorbers greatly increase inproportion to the magnitude of the impacting force and/or the kineticenergy to be absorbed. For use in crash energy management system relatedto vehicular crashworthiness and occupant safety, very little space maybe available to accommodate these conventional shock absorbers.

BRIEF SUMMARY OF THE INVENTION

This disclosure provides a new concept for a compact shock energyabsorber system which can be effectively used for shock mitigation. Onthe basis of a series of laboratory tests and a prototype test performedby the inventors, it is concluded that a significant amount of energycan be absorbed in an impact, explosive blast, or crash event by thepresent invention. Additionally, this class of shock absorption systemcan be scaled up or down and optimized to meet a wide range of impactenergy management scenarios that can be achieved at much lower cost andvery little or no maintenance effort, compared to alternative energyabsorption systems.

The shock energy absorber system described herein can be optimized tolimit the magnitude of peak dynamic force by proper tailoring ofgeometric dimensions and by efficiently absorbing the available kineticenergy of the impacting body within very limited space. This shockenergy absorber can potentially mitigate or minimize the severity ofdamage to property and injury to occupants in a vehicular crash orimpact event.

Examples of the invention provide a new type of shock absorber systemthat utilizes a novel design and a unique elastic-plastic deformationbehavior of Ultra High Molecular Weight (UHMW) Polyethylene or similarmaterials within a confined space when subjected to compressive impactforce. It permits rapid absorption of kinetic energy and limits theimpacting force magnitude through the energy absorption process.Examples include an innovative use of a solid state damping materialthat is available in various grades as Ultra High Molecular WeightPoly-Ethylene (UHMW-PE).

Traditionally, Ultra High Molecular Weight Poly-Ethylene (UHMW-PE) andHigh Density Poly-Ethylene (HDPE) materials have been extensively usedin applications where low friction coefficient and high wear resistanceare of paramount importance. In some instances, UHMW-PE extrudedsections and beams have also been used as buffers such as in watertransportation system docks and locks because of their high flexuralstiffness against lateral impact. Polymeric ballistic materialcomprising a high molecular weight, high density polyethylene (HMW-HDPE)and articles made from this ballistic material have been found suitablefor stopping ballistic projectiles. See also U.S. Patent ApplicationPublication No. 2006/0013977 incorporated herein by this reference.

The inventors have explored and innovatively used cylindrical UHMW-PEbars confined within a metallic cylinder (e.g., steel) or cylinder madeof composite material for absorption of kinetic energy of an impactingplunger with a conical front. This is intended to be used withappropriate scaling and optimized configuration as a part of proposedCrash Energy Management (CEM) system for locomotive crashworthinessapplications. Other potential applications may include other landvehicles such as automobiles and watercraft.

Preliminary investigation including quasi-static testing of UHMW-PEcylindrical bar in a compression test machine offered promising resultsand insight into existence of two distinctly different regimes ofdeformation behavior under compression loading. Computation of energyabsorption from force versus displacement curves of quasi-static testsexhibited potential for its application as a crash energy absorber,provided its high strain rate response behavior under high speed impactcondition is equally promising. In order to evaluate this, a “PendulumImpact Test” was also performed and the test data generated at an impactvelocity of about 17 feet per second supported the concept of effectivehigh energy shock absorption with very little axial deformation of theUHMW-PE material. Additional testing was also conducted.

Featured is a shock absorber comprising damping material in a solidstate and which transitions from a solid to a viscous fluid state whenstressed in compression. A plunger device includes a depending bladepositioned in or adjacent the damping material to be driven into thedamping material when impacted transitioning the damping material to aviscous fluid state absorbing the impact.

In one example, the plunger further includes a plurality of concentricdepending blades. The plunger may include a face plate and concentricround blades depending from the face place. There may also be a railcontaining the damping material. In one example, the rail plunger isthen configured as a beam with a linear blade depending from a topplate.

In one embodiment, an outer cylinder wall is lined with the dampingmaterial, the plunger device includes an inner cylinder having a wallterminating in the depending blade. In one version, the inner cylinderwall is also lined with the damping material. An end cap plunger mayhave a depending blade in or adjacent the damping material lining theinner cylinder wall, a damping material confinement wall depending fromthe end cap, and a strut depends from the end cap inside the confinementwall.

Also featured is a shock absorbing structure comprising a platformincluding damping material in a solid state which transitions from thesolid state to a viscous fluid state when stressed. A plunger includes aface plate, and concentric blades depending from the face plate in oradjacent the damping material to be driven into the damping materialwhen impacted transitioning the damping material to a viscous fluidstate absorbing the impact.

The platform may be in the form of a drop platform. In another version,the platform includes a blast shield securable to the under side of avehicle.

A drop platform in accordance with example of the invention includes abottom surface and damping material in a solid state and whichtransitions from a solid state to a viscous fluid state when stressed onthe bottom surface. A plunger includes a face plate, and concentricblades depending from the face plate in or adjacent the damping materialto be driven into the damping material when impacted transitioning thedamping material to a viscous fluid state absorbing the impact. One ormore side rails each include damping material in a solid state and whichtransitions from a solid state to a viscous fluid state when stressed,and a plunger configured a beam with a blade depending therefromadjacent to or in the damping material to be driven into the dampingmaterial when impacted transitioning the damping material to a viscousfluid state absorbing the impact.

One shock absorber in accordance with an example of the inventionfeatures an outer cylinder wall lined with damping material in a solidstate and which transitions from the solid state to a viscous fluidstate when stressed and a plunger device including an inner cylinderhaving a wall terminating in a depending blade position in or adjacentthe damping material to be driven into the damping material whenimpacted transitioning the damping material to a viscous fluid stateabsorbing the impact confinement wall depending from the end cap.

A shock absorbing method comprises positioning a plunger deviceincluding a depending blade in or adjacent damping material in a solidstate but which transitions from the solid state to a viscous fluidstate when stressed and, upon an impact, driving the depending bladeinto the damping material transitioning the damping material to aviscous fluid state to absorb the energy of the impact.

The subject invention, however, in other embodiments, need not achieveall these objectives and the claims hereof should not be limited tostructures or methods capable of achieving these objectives.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Other objects, features and advantages will occur to those skilled inthe art from the following description of a preferred embodiment and theaccompanying drawings, in which:

FIG. 1 is a schematic front cut away view showing an energy absorber inaccordance with an example of the subject invention;

FIG. 2 is a schematic three-dimensional exploded view of the energyabsorber shown in FIG. 1;

FIG. 3 is a depiction of two halves of a UHMW-PE cylinder tested with aflat-ended threaded steel bar;

FIG. 4 is a graph showing compression load and stress variation with bardisplacement for the test device shown in FIG. 3;

FIG. 5 is a graph showing the variation of instantaneous compressionforce with plunger displacement for a pendulum impact test unit duringimpact at 17.14 feet per second;

FIG. 6A is a force and plunger displacement graph versus time for a 30″drop of a 27 kip hammer in a test using a prototype shock energyabsorber as shown in FIGS. 1 and 2;

FIG. 6B is a graph showing plunger displacement as a function of impactforce magnitude for the prototype shock energy absorber of FIGS. 1 and2;

FIG. 7 is a schematic three-dimensional view showing an example of twoshock energy absorbers mounted to a locomotive;

FIG. 8 is an exploded three-dimensional view showing another example ofa shock energy absorber system in accordance with an example of theinvention; and

FIG. 9 is a schematic three-dimensional view showing the interior of theplunger assembly of FIG. 8;

FIG. 10 is a schematic three-dimensional view showing the shock absorberof FIG. 8 in its assembled state;

FIG. 11A is a schematic three-dimensional view showing another exampleof a shock absorber in accordance with the invention;

FIG. 11B is a schematic cross sectional view of the shock absorber ofFIG. 11A;

FIG. 11C is a schematic view showing in more detail the annular bladesof the plunger portion of the shock absorber of FIGS. 11A and 11B;

FIG. 12A is a schematic three dimensional top view showing an example ofan air drop platform including shock energy absorbing features inaccordance with another example of the invention;

FIG. 12B is another schematic three dimensional view of the shockabsorber of FIGS. 11A and 11B showing how it is positioned with respectto the drop platform of FIG. 12A;

FIG. 12C is a schematic more detailed view showing a rail of the airdrop platform of FIG. 12A;

FIG. 13 is a schematic view showing another example of a shock energyabsorber attached to the bottom of a military vehicle in the form of ablast shield;

FIG. 14A is a schematic three dimensional front view showing stillanother example of a shock absorber in accordance with the invention;

FIG. 14B is a schematic cut away view of the shock absorber of FIG. 14A;and

FIG. 14C is a more detailed view showing a portion of the shock absorberof FIG. 14B.

DETAILED DESCRIPTION OF THE INVENTION

Aside from the preferred embodiment or embodiments disclosed below, thisinvention is capable of other embodiments and of being practiced orbeing carried out in various ways. Thus, it is to be understood that theinvention is not limited in its application to the details ofconstruction and the arrangements of components set forth in thefollowing description or illustrated in the drawings. If only oneembodiment is described herein, the claims hereof are not to be limitedto that embodiment. Moreover, the claims hereof are not to be readrestrictively unless there is clear and convincing evidence manifestinga certain exclusion, restriction, or disclaimer.

A novel compact high energy shock absorber can preferably be made ofvery few machined parts. The major components in one example are shownin FIGS. 1-2. Shock energy absorber 10 includes vessel 12, in thisparticular example, a cylinder with closed end 14 a and open end 14 b.In this example, flange 16 is included at closed end 14 a for mountingcylinder 12 to a structure such as a locomotive or other vehicle or thebottom of an elevator shaft or the like.

Damping material 18 (e.g., UHMW-PE material) in its solid state isplaced in and confined within cylinder 12. Typically, the dampingmaterial radially fills the cylinder for most of the length of thecylinder. Plunger 20 is positioned to be driven into damping material18. In this particular example, sleeve 22 is provided and fixed aboutthe open end of cylinder 12 via fasteners 24. Sleeve 22 includes bearing26 about plunger 20. Plunger 20 in this example includes conical end 28,hollow shaft portion 30 (for weight reduction), and flange portion 32.Damping material 18 may include seat 34 receiving conical end 28 ofplunger 20.

The cylinder is preferably made of high strength alloy steel and ofseamless construction with a larger wall thickness to safely withstand ahigh magnitude of hoop stress. The UHMW-PE cylindrical specimen is madeto snug-fit with the inner diameter of the cylinder. At the center ofthe UHMW-PE specimen, a small diameter through hole can be included toguide the vertex of the conical-front plunger during impact. The plungeris also made of high strength alloy steel and its dimensions areselected to leave adequate clearance between the inner diameter ofcylinder and the outer diameter of the plunger. The plunger may be madeof a solid steel bar or a hollow steel bar of large wall thickness. Itslength should be adequate to achieve the maximum stroke or traveldesired under the action of the impact force. The steel sleeve fittedwith a bearing is intended to offer lateral support and guide theplunger to travel coaxially along the centerline of the UHMW-PE materialupon impact. The sleeve is screwed down to the outer surface of thecylinder for adequate support and proper alignment of the axis ofplunger with that of the UHMW-PE cylinder. The cylinder and the plungercan both provided with circular flanges at their bases which haveprovision for attachment to corresponding mating surfaces or plates witha number of fasteners. If necessary, the rear (striking) end of theplunger may be left unattached to any surface depending on theconfiguration of the vehicle or structure or when the plunger isrequired to contact directly with an impacting body.

In a typical application, the geometric dimensions of the shock energyabsorber will be tailored to limit the desired highest impact forcemagnitude, depending on the strength of the reaction surface to whichthe cylinder block is mounted, and the maximum travel of the plungercommensurate with the required kinetic energy absorption. The componentsof the system are mounted to the required position while ensuring theirproper alignment.

When the impacting body or object strikes the rear end (32, FIGS. 1-2)of the plunger with adequate momentum, its conical front-end presseshard against the UHMW-PE cylinder and penetrates it, which, in turn,offers a reaction force to decelerate the motion of the plunger. Withthe plunger continuing to press on against the UHMW-PE, when a criticalstress magnitude is reached, the UHMW-PE material undergoes a phasetransition from solid to a viscous fluid state. This phase transitionoccurs within a confined space and at or above a critical compressiveflow stress magnitude based on the plunger area of cross-section. In onelaboratory test, it has been observed to be a reversible process in thatupon releasing the high stress magnitude, the viscous UHMW-PE materialregains its solid state. Upon impact, the plunger with the conical frontpenetrates into the front end of the UHMW-PE cylinder. With theincreasing impact force magnitude, the UHMW-PE material undergoes phasetransition at or above the critical flow stress. As the UHMW-PE materialahead of the plunger transitions into viscous fluid state, the resistingforce on plunger drops sharply to a lower value. The plunger would thencontinue to move with a gradual further rise in force magnitude untilthe end of the plunger's travel is reached or until the impact energy isabsorbed. The maximum impact force experienced by the structuresupporting the cylinder may be slightly more than that developed by theplunger corresponding to the critical stress of the UHMW-PE materialused. Total energy absorbed by the shock energy absorber during theimpact would be nearly equal to the work done by the plunger on theUHMW-PE cylinder.

This shock energy absorption system embodies a new concept and ispresently not known to be used by any industry. The compact systemrequires less space to accommodate it and less travel distance of theplunger to absorb a high amount of impact energy. It offers scope fordimensional optimization to limit the desired peak impact forcemagnitude. It utilizes a low cost, UV-resistant solid UHMW-PE or similarmaterial for shock absorption. In real life applications, an installedunit requires very little or no maintenance over long time periodwithout any risk of leaking hydraulic fluid as in some alternative shockabsorption systems.

The inventors performed a compression test using an INSTRON Model 8502servo-hydraulic test machine. The test specimen was a 2.5 in diameterUHMW-PE solid bar inserted inside a seamless steel cylinder that wasmounted over the actuator of INSTRON test machine. The initial plungerwas a conical front 2.0 in diameter steel plunger, which failed topenetrate the UHMW-PE specimen even at safe machine load capacity of 50kilo-pound (kip), although it made a dimpled impression on the specimensurface. The inventors replaced the conical front plunger with a fullythreaded 1.0 in diameter and 3.0 in long flat-ended steel bar that wasreadily available and performed the compression test on the same testspecimen. During the test, it was noted that initially the compressionforce gradually increased with threaded bar displacement into theUHMW-PE cylinder up to about 1.0 inch when the force magnitude wasapproximately 20 kip. Beyond that point the force magnitude almostremained constant with increasing displacement of the threaded bar. Thetest was stopped at a maximum displacement of about 1.7 inches and thetest specimen was unloaded. Later, the inventors tried unsuccessfully toremove the threaded bar from the UHMW-PE specimen. The UHMW-PE cylinderwas then cut open along a diametric plane on its back face to remove thethreaded bar. After cutting the UHMW-PE cylinder into two halves, thethreaded bar popped out of the groove revealing thread impressionsinside the groove in both halves of the UHMW-PE cylinder.

FIG. 3 shows the two halves 40 a and 40 b of the UHMW-PE cylinder,including the thread impressions inside the grooves and the flat-endedthreaded steel bar 42 used in the above test.

From FIG. 3 it is seen that there are solidified UHMW-PE materialdeposit in the shape of raised triangular mass just ahead of theend-position of the flat-ended steel bar. This raised triangular UHMW-PEmaterial is seen in both halves of the cut-cylinder, which shows clearevidence of later local oozing out, solidification, and increase involume of viscous-state UHMW-PE material after the cylinder was cutopen. The thread impressions in both halves are also suggestive of asofter viscous state of the core material adjacent to the threaded steelbar that was “locked-in-place” and that solidified following the removalof load in the test machine.

FIG. 4 shows graphical representation of the above test results plottedas compression load and compression stress versus the displacement ofthe threaded bar into the UHMW-PE cylinder. These graphs show thatbeyond approximately 20 kip load or about 25 ksi stress, the coreUHMW-PE material did not offer further increasing resistance and thesubsequent displacement of the threaded bar took place at almost thesame compressive load/stress level, associated with the phase transitionof the highly stressed UHMW-PE core material. The compression stressmagnitude mentioned here is based on the cross-sectional area of theplunger.

FIG. 5 shows a graphical representation of the dynamic force versusplunger displacement obtained from a typical impact test conducted at17.14 feet per second impact velocity.

A prototype unit similar to FIGS. 1-2 was also fabricated and tested.The diameter of damping material 18 was 9.5″ and the plunger 30 had adiameter of 3″.

FIG. 6A shows force and plunger displacement as a function of time for30″ drop of a 27 kip hammer testing device impacting flange end 32 ofplunger 20. A reversible phase transition of the damping material wasclearly observed. The peak force was approximately 180 kips and thekinetic energy absorbed was approximately 82,260 ft-lb. As shown in FIG.6B the phase transition of the UHMW-PE material occurred atapproximately 2 inches of plunger displacement. By scaling the shockenergy absorber, it is possible to tailor the peak crash energyabsorption up to any desired value. The cylinder serves as a compressionvessel for the UHMW-PE material. Important design criteria include theimpact velocity, the cross-sectional area of the damping material, andthe plunger diameter.

FIG. 7 shows two larger shock absorbers 10 a and 10 b of the typedepicted in FIGS. 1 and 2 attached to locomotive 50. Other uses for theshock absorber include end of rail track buffers, crash energy absorbersat the bottom of elevator shafts, use in rail tank cars to preventpuncture of a tank in the event of a collision and/or derailment, shockabsorbers used in conjunction with road tankers and hazmat carryingtrucks, and chassis front end shock absorbers of automobiles and transitbuses. In all examples, a significant amount of energy is absorbed dueto the transition of the damping material from a solid to a viscousfluid and the consequent plunger displacement.

In general, vessel 12 and/or plunger 32 is fixed to a structure. Theplunger is driven into the damping material by moving the plunger andthe shock absorber to strike an object or by moving an object to strikethe structure and the shock absorber. When this occurs, the dampingmaterial changes from a solid state to a viscous fluid state and absorbsthe energy associated with the impact. Alternatively, a shock absorbercan be mounted between two objects or structures.

FIG. 8 shows another design including cylinder 60 housing spring 62,buffer plate 64, and damping material 68 therein. Plunger assembly 70,also shown in FIG. 9, includes plunger 72 positioned to be driven intodamping material 68 via bearing sleeve assembly 74, FIG. 8. Again,damping material 68 may include seat 76. FIG. 10 shows the assembledshock energy absorber unit where plunger assembly 70 is coupled overcylinder 60 and plunger 72, FIG. 9 now abuts damping material 68, FIG.8.

Shock absorber 100 in accordance with another example with of theinvention includes damping material 102 in a solid state and which, asdescribed above, transitions from a solid to a viscous fluid state whenstressed in compression. Examples include ultrahigh molecular weightpolyethylene, HDPE, and equivalents thereof. A constraining frame 104 isoptional in the particular example depicted. Plunger device 106 includesdepending blades 108 a-108 b as shown in FIGS. 11B and 11C. The bladestypically terminate in pointed knife portion 110 as shown for blade 108d, FIG. 11C positioned or closely adjacent to damping material 102.Plunger 106 is impacted and the blades are driven into the dampingmaterial transitioning it from a solid to a viscous fluid stateabsorbing the energy of the impact through work done by the plunger. Asopposed to a solid plunger as depicted with respect to FIGS. 1 and 2,the round concentric series of blades 108 a-108 d which depend downwardfrom base plate 112 of plunger 106 are lighter in weight and serve toconstrain flow of material 102 to the space between adjacent blades. Inone embodiment, shock absorber 100 is positioned underneath andapproximately in the center of air drop platform 120, FIG. 12A. Thedamping material is secured to the bottom of the drop platform with aplunger facing downward toward the ground. The plunger does not have tohave to be domed, nor does it have to be inclusive of a drop platform.

FIG. 12C shows how platform rail 122 a may include damping material 124.Here, the plunger is configured as beam 126 with linear blade 128depending from top plate 130.

In still another example, blast shield 140, FIG. 13A includes a platelike structure made up of the damping material discussed aboveoptionally within a frame as shown at 142 secured to the under carriageof military vehicle 144. Another example, shown, FIG. 13B of the sameunder carriage configuration could include a rectangular pattern asopposed to a circular (annular) configuration of blades radiatingoutward from the center as depicted in FIG. 11A in a sandwichconstruction containing amour plate, damping material, annular bladesand blast shield. In one embodiment, shock absorber 100, FIG. 11A isplaced between the vehicle frame and optional blast shield 140 in itscenter. In other designs, more than one shock absorber 100 is depictedin FIG. 11A circular or rectangular in configuration may be placedbetween the vehicle frame and blast shield 140.

FIGS. 14A-14C show a design where outer cylinder telescoping walls 150 &154 with damping material 152 sandwiched in between the inner slidingconfinement cylinder 162 which depends downward from the circular blade160 which travels together during compression. Here the plunger deviceincludes inner telescoping cylinder wall 154 terminating in dependingblade 156. In this example, the strut when acted upon by a forceexceeding its capacity depend downward acting upon the circular blade160 and the inner telescoping cylinder 154. The depending blade 156which is in contact with the damping material 152 begins to compress thedamping material 152 and being confined by the outer telescopingcylinder walls and the inner sliding confinement cylinder. The design issuch that upon impact circular knife edge 156 typically driven into thedamping material before circular knife edge 160 is driven into dampingmaterial due to difference of area under respective knife edges. Thecombined effect of both, cause the damping material to go into phasechange in different areas of the damping material column. In anotherexample the inner confinement cylinder could be telescoping. Preferably,inner cylinder wall 154 is also lined with the damping material as shownand end cap plunger 158 includes depending circular blade 160 adjacent atop edge of the damping material 152 lining inner cylinder wall 154. Inthis example, damping material confinement wall 162 depends downwardfrom end cap structure 158 which also includes a strut 164 positionedwithin confinement wall 162. In some examples, confinement wall 162 mayterminate some distance from collar structure 166 which contains thedistal end of outer cylinder wall 150 and which also supports dampingmaterial 152. The design is such that upon impact circular knife edge156 typically driven into the damping material before circular knifeedge 160 is driven into the damping material.

Linear strip type plungers with a knife edge, annular plungers with aknife edge, are thus configured to impact the damping material typicallyenclosed within a confined space, because concentric blades beingcircular or rectangular in pattern create a confinement duringcompression.

Although specific features of the invention are shown in some drawingsand not in others, this is for convenience only as each feature may becombined with any or all of the other features in accordance with theinvention. The words “including”, “comprising”, “having”, and “with” asused herein are to be interpreted broadly and comprehensively and arenot limited to any physical interconnection. Moreover, any embodimentsdisclosed in the subject application are not to be taken as the onlypossible embodiments.

In addition, any amendment presented during the prosecution of thepatent application for this patent is not a disclaimer of any claimelement presented in the application as filed: those skilled in the artcannot reasonably be expected to draft a claim that would literallyencompass all possible equivalents, many equivalents will beunforeseeable at the time of the amendment and are beyond a fairinterpretation of what is to be surrendered (if anything), the rationaleunderlying the amendment may bear no more than a tangential relation tomany equivalents, and/or there are many other reasons the applicant cannot be expected to describe certain insubstantial substitutes for anyclaim element amended.

Other embodiments will occur to those skilled in the art and are withinthe following claims.

1. A shock absorber comprising: damping material in a solid state andwhich transitions from a solid to a viscous fluid state when stressed incompression; and a plunger device including a depending blade positionedin or adjacent the damping material to be driven into the dampingmaterial when impacted transitioning the damping material to a viscousfluid state absorbing impact energy.
 2. The shock absorber of claim 1 inwhich the plunger further includes a plurality of concentric dependingblades.
 3. The shock absorber of claim 2 in which the plunger includes aface plate and the concentric blades depend from the face plate.
 4. Theshock absorber of claim 2 in which the blades are round.
 5. The shockabsorber of claim 1 further including a rail containing the dampingmaterial.
 6. The shock absorber of claim 5 in which the plunger isconfigured as a beam with a linear blade depending from a top plate. 7.The shock absorber of claim 1 further including an outer cylinder walllined with said damping material.
 8. The shock absorber of claim 7 inwhich the plunger device includes an inner cylinder having a wallterminating in said depending blade.
 9. The shock absorber of claim 8 inwhich said inner cylinder wall is also lined with said damping material.10. The shock absorber of claim 9 further including an end cap plungerwith a depending blade in or adjacent damping material lining said innercylinder wall.
 11. The shock absorber of claim 10 further including adamping material confinement wall depending from said end cap.
 12. Theshock absorber of claim 11 further including a strut depending from theend cap inside the innermost confinement wall.
 13. A shock absorbingstructure comprising: a platform including damping material in a solidstate which transitions from the solid state to a viscous fluid statewhen stressed under compression; and a plunger including: a face plate,and concentric blades depending from the face plate in or adjacent thedamping material to be driven into the damping material when impactedtransitioning the damping material to a viscous fluid state absorbingthe impact.
 14. The shock absorbent structure of claim 13 in which theplatform includes a drop platform.
 15. The shock absorbent structure ofclaim 13 in which the platform includes a blast shield securable to theunder side of a vehicle.
 16. A drop platform comprising: a bottomsurface; damping material in a solid state and which transitions from asolid state to a viscous fluid state when stressed under compression onsaid bottom surface; a plunger including: a face plate, and concentricblades depending from the face plate in or adjacent the damping materialto be driven into the damping material when impacted transitioning thedamping material to a viscous fluid state absorbing the impact; and oneor more side rails including: damping material in a solid state andwhich transitions from a solid state to a viscous fluid state whenstressed, and a plunger configured a beam with a blade dependingtherefrom adjacent to or in the damping material to be driven into thedamping material when impacted transitioning the damping material to aviscous fluid state absorbing the impact.
 17. A shock absorbercomprising: an outer cylinder wall lined with damping material in asolid state and which transitions from the solid state to a viscousfluid state when stressed in compression; and a plunger device includingan inner cylinder having a wall terminating in a depending bladeposition in or adjacent the damping material to be driven into thedamping material when impacted transitioning the damping material to aviscous fluid state absorbing the impact.
 18. The shock absorber ofclaim 17 in which said inner cylinder wall is lined with said dampingmaterial.
 19. The shock absorber of claim 18 further including an endcap plunger with a depending blade in or adjacent the damping materiallining said inner cylinder wall.
 20. The shock absorber of claim 19further including a damping material confinement wall depending fromsaid end cap.
 21. The shock absorber of claim 20 further including astrut within the confinement wall.
 22. The shock absorbing methodcomprising: positioning a plunger device including a depending blade inor adjacent damping material in a solid state but which transitions fromthe solid state to a viscous fluid state when stressed; and upon animpact, driving the depending blade into the damping materialtransitioning the damping material to a viscous fluid state to absorbthe energy of the impact.